Formation of Rod-Like Particles with Periodic Interior by Hydroxypropylmethyl Cellulose Samples with Narrow Molar Mass Distributions in Aqueous Solutions

The structure and conformation of hydroxypropylmethyl cellulose (HpMC) samples (<i>DS</i> = 1.8 and <i>MS</i> = 0.15) with narrow molar mass distributions of <i>M</i>_w/<i>M</i>_n ≤ 1.3 at <i>M</i>_w of 210, 310, and 440 kg mol^-1 dissolved in aqueous solution were investigated using static light scattering (SLS) and small angle neutron scattering (SANS) techniques to cover a wide scattering vector (<i>q</i>) range. The <i>q</i> dependencies of the concentration-reduced excess Rayleigh ratios via SLS at the extrapolated zero-concentration were smoothly linked with those of the concentration reduced excess scattering intensities via SANS using the same factor for all the HpMC samples. The linked scattering intensity curves were reasonably described with the form factor of monodisperse rod particles. Moreover, broad interference scattering peaks possibly exist at <i>q</i> ∼ 0.042 nm^-1 in the linked scattering curves, suggesting the presence of a periodicity of ∼150 nm in the rod-like particles formed by HpMC molecules.